My website is getting AVG alert.. Please help me to get rid off this.

I installed AVG free antivirus few days ago. When i was checking my websites I got AVG alert for one of the websites and it refused to open. It is a sales page and I am sure other AVG users will also be notified the same. Please help me to get rid off this error. I have attached the screenshot. Please give your advise. It is really urgent.

I installed AVG free antivirus few days ago. When i was checking my websites I got AVG alert for one of the websites and it refused to open. It is a sales page and I am sure other AVG users will also be notified the same. Please help me to get rid off this error. I have attached the screenshot. Please give your advise. It is really urgent.